Ocular device



E. A. ZENATTl May 24, 1955 OCULAR DEVICE Filed March 2, 1954 A m. Mm y/ /l/l/l/ IV A v INVENTOR EMILE A. Zsmqrrz WWW ATTORNEYS United States Patent "ice OCULAR DEVICE Emile Armand Zenatti, Paris, France Application March 2, 1954, Serial No. 413,672 Claims priority, application France October 27, 1948 8 Claims. (Cl. 128--2.05)

This application is a continuation in part of my prior application Ser. No. 122,224, filed on October 19, 1949, for: Sphygmograph Adapted for the Examination of Patients Eyes, and now abandoned.

The present invention relates to an apparatus for exerting a pneumatic compression of the eye-ball and studying the effects resulting therefrom.

' It is most beneficial to exert upon a given area of the wall of the eye-ball a pressure which may be accurately measured and to study in the area thus subjected to such compression effect or even in a place remote from said area, the effects resulting from such a compression.

Investigators who endeavoured to carry out such experiments encountered considerable difiiculties the most important of which, no doubt, is the great mobility of the eye in alive condition. Apart from the ocular movements connected to patients emotion or fatigue, the human eye is never motionless and even when staring it is subject at very close time intervals to uncontrolled movements that the patient is unable to check in spite of his willingness to do so. This is a normal physiological instability. The operator is thus seeking a test field that is permanently in motion and the tests and the observations are thus interrupted by discontinuous stops in the course of which he must endeavour to re-establish the same experimental conditions.

The operator who holds in his hand an experimental device adapted to be applied against the eye, furthermore adds his own instability and, besides, continuously varies, namely increases or decreases, the effort which is necessary'for maintaining this device against the eye. Hence, due to the presence of this manual effort, he unintentionally introduces a source of errors into the value of the compression he achieves and which he is unable to define. I

Assuming any sort of frame could be substituted for the operators hand for applying the device against the eye, the mobility of the eye is always liable to interfere and move the 'experimentalfields. r

' The accuracy in the study of the phenomena resulting from the compression of the eye-ball together with the-continuous observation of the experimental facts require the experimental device to be firstly independent from'the operator and self-acting and secondly rigidly connected to theeye-ball so as to move in perfect unison therewith.

To such major qualities as independency on the operator and rigid connection tothe eye-ball, useful minor qualities may be added as will now appear. Some phenomena appear under a very small compression and are destroyed by a compression which reaches a stronger magnitude. The accuracy of the results obtained is thus entranced by a compression achieved in as small increments as possible and by using a device of a Weight as light as possible. 7

' The object of this invention is to meet such major and minor requirements.

According to a main feature of this invention the 2,708,928 Patented May 24, 1955 device independent from the operator and adapted to be made perfectly rigid with the eye-ball is constituted by a suction cup made of plastic material or rubber for instance, of a very flexible character.

It has an outer convex surface and a concave inner ocular surface which is perfectly smooth and adapted to accommodate any ocular wall since the flexibility of the cup material makes it possible for this inner surface to vary its radius of curvature. The central portion of the suction cup is extremely thin and flexible.

Such a suction cup applied against the eye-ball by a gentle manual pressure which results in the air contained in the cup to be expelled, adheres to the wall of the eye-ball and from that moment on keeps adhering thereon solely under the action of the atmospheric pressure, and accordingly moves together with the eyeball which is, as already stated above, so as to say never at standstill.

With a view to transfer a pneumatic pressure to the eyeball, the outer surface or crown of the suction cup has an extension in the form of a hollow body which constitutes a cylindrical sleeve with non-ext nsible lateral walls. The upper portion of said hollow body is closed, while the lower portion thereof is obturated by the very thin membrane provided in the central portion of the holding suction cup and, hence, common to said cup and to said closed sleeve or chamber. An inlet for air under pressure opens into said chamber which thus becomes the device which makes it possible for the compression to be applied to the eye-ball through the medium of the very thin and flexible membrane common to the holding suction cup and to the compression chamber.

The use of a pneumatic pressure allows this compression to be varied with the desired degree of progressivity.

Such a device for compressing the eye-ball, rigidly connected thereto while at the same time quite independent from either the operator or any other means for holding said device against the eye, may be used for studying many physiological problems in connection with the eye such as the measurement of the elasticity of the eye wall, measurement of the flow pressure of the aqueous humour, and so on. However, it is particularly for the measurement of the intro-ocular pressure as well as for that of the blood pressures within the intra-ocular vessels that this device may be applied most instructively.

Under the effect of compression, two phenomena occur in the wall of the eye-ball, namely a yieldingor sinking phenomenon (tonometric phenomenon) the magnitude of which varies with the value of the intra-ocular pressure, and a pulsating phenomenon (oscillometric phenomenon) which results from the alternating diastoles and systoles brought about by the compression.

The resilient membrane which is applied against the wall of the eye-ball and subjected to the outer and inner pressures follows faintly these movements of the wall of the eye-ball which have an extremely short amplitude of the order of a few tenths of a millimeter for tonometry and a few hundredths of a milimeter for oscillometry.

In order to make it possible for such movements to be measured and recorded, they are electrically amplified in the following manner.

The top portion of the compression chamber is surrounded by a solenoid through which a high frequency current is circulated. Coincident with the axis of the compression chamber is a movable rod the lower end of which rests upon the eye through the medium of the thin membrane of the suction cup and the upper end of which carries a metal core or piston arranged within the solenoid.

The movements of said core cause the strength of the high frequency current to be varied. This current which is amplified and rectified controls two photo recording oscillographs. The first of these oscillographs indicates the large amplitude movements whereas the second indicates only the oscillations adapted to provide for ocular oscillornetry. In this manner, there is obtained an electronic detector or pickup the weight of which may be as small as 2.5 grams and which makes it possible to simultaneously record the pneumatic compression exerted, the tonomctric curve and the oscillometric curve.

The accompanying drawing diagrammatically shows in axial section an electronic detector in engagement with an eye-ball to which it adheres only by virtue of the atmospheric pressure without the help of any other holding means.

The suction cup as illustrated in the drawing comprises a body 1 made of rubber and which is formed into the cup proper 2 the bottom of which is constituted by a very thin and flexible membrane 3. The body 1 is formed with a cylindrical extension 4 terminating into an outwardly turned flange 5. The body 1 is mounted on a cylindrical metal case 6, preferably of light metal alloy, by means of a threaded ring 7 screwed over the adjacent end of said case. Inside the case 6 is arranged a rod 8 one end of which is formed into a feeler 9 which is in bearing engagement with the membrane 3. The rod 8 is adapted to slide freely Within a guiding member constituted by a washer 10. On the end of the rod 8 remote from the feeler carrying end is secured a core 11 and a solenoid 12 is embedded in a cylinder 15 of plastics arranged around the case 6. The case 6 is provided with a nipple 13 over which is slipped a rubber hose 14. The interior of the case and of the cup constituted by the body 1 forms the compression chamber. In order to admit compressed air into said compression chamber the hose 14 is connected to a compressed air supply.

When it is desired to use the device it is sufficient to secure it against the eye of the patient who is lying so that the compression chamber be in a vertical direction, and for that purpose it suffices to exert a gentle manual pressure upon the device so that the suction cup 2 perfectly fits over the wall of the eye-ball 16 by virtue of the atmospheric pressure alone since all the air initially entrapped between the suction cup and the eye-ball has been expelled by the manual presure exerted upon the f suction cup. The air under presure is then gradually admitted into the compression chamber 6 through the nipple 13 and the electrical winding 12 connected to a high frequency current supply. As hereinabove explained all the vibrations experienced by the wall of the eye-ball are transferred to the membrane 9, the pick-up rod 8 and the core 11. This results in variations in the high frequency current circulated through the winding 12 which may be thoroughly studied by means of oscillographs as hereinabove indicated.

I have described a preferred embodiment of my invention, but it is clear that numerous changes could be made without departing from the scope of the invention as defined in the following claims.

What I claim is:

l. Ocular detector comprising in combination a holding suction cup of flexible material adapted to adhere to the eye-ball by a mere manual pressure exerted upon said suction cup, and to be rigidly secured to the eye-ball by the effect of atmospheric pressure only, a very thin and flexible membrane forming the crown portion of said holding suction cup and the under surface of which is adapted to be in bearing engagement with the outer surface of the eye-ball to which said suction cup is adapted to adhere, a compression chamber carried by said holding suction cup and one wall of which is formed by the upper face of said membrane, inlet means through a wall portion of said compression chamber adapted to provide a communication between said compression chamber and a source of pressure fluid; and means car- 4 ried by said compression chamber for analysing the movements imparted to said membrane by the wall of the eye-ball upon the pressure which prevails in said compression chamber being applied to the wall of the eyeball through the medium of said membrane.

2. Ocular detector comprising in combination a holding suction cup of flexible material adapted to adhere to the eye-ball by a mere manual pressure exerted upon said suction cup and to be rigidly secured to the eye-ball by the effect of atmospheric pressure only, a very thin and flexible membrane forming the crown portion of said holding suction cup and the under surface of which is adapted to be in bearing engagement with the outer surface of the eyeball to which said suction cup is adapted to adhere, a compression chamber carried by said holding suction cup and one wall of which is formed by the upper face of said membrane, inlet means through a wall portion of said compression chamber adapted to provide a communication between said compression chamber and a source of pressure fluid, a pick-up member mounted for reciprocating movement within said compression chamber in bearing engagement with said membrane, a magnetic core carried by said pick-up member, and an electric winding with two leads carried by said compression chamber and surrounding said magnetic core.

3. Ocular detector comprising in combination a holding suction cup of flexible material adapted to adhere to the eye-ball by a mere manual pressure exerted upon said suction cup and to be rigidly secured to the eye-ball by the effect of atmospheric pressure only, a very thin and flexible membrane forming the crown portion of said holding suction cup and the under surface of which is adapted to be in bearing engagement with the outer surface of the eye-ball to which said suction cup is adapted to adhere, an elongated compression chamber carried by said holding suction cup and one end wall of which is formed by the upper face of said membrane, inlet means through a lateral wall portion of said compression chamber adapted to provide a communication between said compression chamber and a source of pressure fluid, a pick-up rod mounted coincident with the longitudinal axis of said elongated compression chamber and resting upon the upper face of said membrane when said compression chamber is positioned on the eyeball substantially in a vertical direction, said pick-up rod being adapted for reciprocating movement within said compression chamber along the axis thereof, a magnetic core carried by said pick-up rod on the end portion thereof remote from the end of said rod which is in bearing engagement with said membrane, and an electric winding with two leads carried by said compression chamber and surrounding said magnetic core.

4. Ocular detector as covered by claim 3, with the provision of a guiding member for said pick-up rod secured within said compression chamber adjacent the end portion of said rod which is adapted to rest upon the upper face of said membrane.

5. Ocular detector as covered by claim 3, wherein the end portion of said pick-up rod remote from the end thereof adapted to bear against said membrane is mounted for free longitudinal reciprocating movement within a bore of the rigid end wall of said elongated compression chamber.

6. Ocular detector as covered by claim 3, wherein said electric winding is embedded in a tubular body of plastic material fixedly secured to the outer lateral wall of said elongated compression chamber.

7. Ocular detector comprising in combination a holding suction cup of flexible material adapted to adhere to the eye-ball by a mere manual pressure exerted upon said suction cup and to be rigidly secured to the eye-ball by the effect of atmospheric pressure only, a very thin and flexible membrane forming the crown portion of the inner face of said holding suction cup and the under surface of which is adapted to be in bearing engagement with the outer surface of the eye-ball to which said suction cup is adapted to adhere, a tubular extension on the outer face of said holding suction cup formed with an outwardly turned flange, an elongated casing with an upper closed end and a lower open end, having an outer threaded portion, said casing being adapted to be carried by said tubular extension of said suction cup with its bottom peripheral edge in sealing engagement with said flange of said tubular extension, said casing forming together with said membrane a compression chamber, in let means through the lateral Wall of said casing adapted to provide a communication between said compression chamber and a source of pressure fluid, a fastening ring formed with an inwardly extending flange adapted to bear against the lower face of said flange of said tubular extension and having an internally threaded portion adapted to come into threading engagement with said outer threaded portion of said casing in order to hold said casing in sealing engagement against said tubular extension, a pick-up rod mounted in said elongated casing coincident with the longitudinal axis of said elongated casing and resting upon the upper face of said membrane when said compression chamber is positioned on the eye-ball substantially in a vertical direction, said pick-up rod being adapted for reciprocating movement within said compression chamber along the axis thereof, a magnetic core carried by said pick-up rod, and an electric Winding with two leads carried by said elongated casing in a location surrounding said magnetic core.

8. Ocular detector as covered in claim 7, with a guiding member formed by a washer the peripheral portion of which is pressed between the upper face of said flange of said tubular extension and the lower bottom edge of said tubular casing, said pick-up rod being freely guided in the bore of said Washer, an axial recess being provided in said closed upper end portion of said elongated casing having a size slightly in excess of the size of the upper end portion of said pick-up rod for freely maintaining said pick-up rod coincident with the axis of said 20 casing while allowing said rod to reciprocate.

No references cited. 

